In wireless devices, there can be multiple radio architectures, or radio access technologies (RAT). Example standards that may be supported on a wireless device, include Universal Mobile Telecommunication System (UMTS) 3rd Generation (3G), Long Term Evolution (LTE) 4, LTE 10 and LTE 20. Each architecture or standard operates in particular bandwidths, and has particular resource and power (current) requirements as to receiving and transmitting.
A wireless device with multiple RATs, may have to support the different bandwidth requirements of each RAT. In particular, radio frequency (RF) transmitters, receivers, transceivers, and modems of the wireless device may have to support different bandwidths. For example, transmission bandwidth for UMTS 3G may be 1.5 MHz wide and LTE 20 may have a 38 MHz bandwidth.
As bandwidth increase, the power and resource requirements also increase. For wireless devices, physical resource blocks (PRB). PRB are groups of transport carriers (e.g. sub-carriers) or intervals that are assigned to transport data. For example, a wireless device with multiple RATs, may include an architecture with LTE 20. The LTE 20 architecture may be allocated 100 PRBs. Other collocated RATs on the wireless device (e.g., UMTS 3G, LTE 10) may operate at lower bandwidths and lower power. These collocated RATs require less PRBs. Furthermore, although LTE 20 may be allocated 100 PRBs, typically only a fractional portion of the 100 PRBs are actually used. For example, in LTE 20 transmission may only 25 PRBs are used, which is the maximum number used by LTE 5. These instances exist, such as in frequency domain division where multiple users operate at the same band. In certain instances, a acknowledge signal is sent requiring nominal PRBs. The use of fewer PRBs also has advantageous in signal to noise ratio (SNR). The PRBs that are used divide the output power. Therefore, with output power remaining constant (i.e., full output power), the fewer the PRBs, the more power for each PRB, thus increasing SNR for each PRB.
Accuracy is related to power (output power), current usage, and bandwidth. In particular, accuracy is related operating clock frequency supporting particular RATs/standards. Operating clock frequency at a wireless device may be adjusted per RAT/standard.
As such, there is a need to provide efficient power consumption and communication in multi RAT wireless devices.